Headrest support device

ABSTRACT

Provided is a simple and compact headrest support device. The headrest support device (20) comprises a support member (22) coupled to a frame (2) of a seatback (1), and a headrest pillar structure including a pillar base portion (25) extending laterally and supported by the support member so as to be rotatable around an axial line of the pillar base portion, and a pair of pillar main body portions (26) extending substantially vertically from the pillar base portion substantially in parallel to each other in a laterally spaced apart relationship and connected to a headrest (24), wherein the support member is coupled to the frame at at least one coupling portion (34) disposed between the two pillar main body portions in front view in a headrest upright condition where the headrest is positioned above the seatback.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage entry of InternationalApplication Number PCT/JP2016/003613 filed under the Patent CooperationTreaty having a filing date of Aug. 4, 2016, which claims priority toJapanese Patent Application Number 2015-154057 having a filing date ofAug. 4, 2015, which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a headrest support device, and inparticular to a headrest support device that allows a headrest to beangularly adjusted relative to a seatback.

BACKGROUND ART

A known headrest support device for a vehicle seat supports a headrestso as to be angularly adjusted relative to a seatback (see PatentDocument 1, for example). The headrest support device disclosed inPatent Document 1 includes a pillar structure including a pair of rightand left leg portions having lower ends coupled to a seatback and ahorizontal rod portion connected between the upper ends of the legportions, a main frame rotatably supported by the horizontal rodportion, and a cover material that covers the main frame. The headrestis completed by covering the cover material with a pad material and askin member.

PRIOR ART DOCUMENT(S) Patent Document(s)

Patent Document 1: JP5038735B

SUMMARY OF THE INVENTION Task to be Accomplished by the Invention

In the headrest support device disclosed in Patent Document 1, since themain frame is formed by joining two metal plate members by crimping orthe like, a special tool is required for assembly. In addition, since alatch plate provided on the horizontal rod portion for selectivelysecuring the main frame to the pillar structure protrudes out of themain frame, the cover material is required to cover both the main frameand the latch plate. Therefore, the headrest support device requires alarge number of component parts, tends to be complex in structure, andis inevitably large in size.

The present invention was made in view of such problems of the priorart, and has a primary object to provide a headrest support device whichis simple in structure, and compact in size.

Means for Accomplishing the Task

To achieve such an object, the present invention provides a headrestsupport device (20) comprising: a support member (22) coupled to a frame(2) of a seatback (1); and a headrest pillar structure including apillar base portion (25) extending laterally and supported by thesupport member so as to be rotatable around an axial line of the pillarbase portion, and a pair of pillar main body portions (26) extendingsubstantially vertically from the pillar base portion substantially inparallel to each other in a laterally spaced apart relationship andconnected to a headrest (24); wherein the support member is coupled tothe frame at at least one coupling portion (34) disposed between the twopillar main body portions in front view in a headrest upright conditionwhere the headrest is positioned above the seatback.

According to this aspect of the present invention, since the at leastone coupling portion is disposed in a space surrounded by the headrestpillar structure in a headrest use position in front view, the supportmember and the headrest pillar structure can be arranged compactly, andthe size of the headrest support device can be minimized.

Preferably, the coupling portion includes a first coupling portion (34)disposed between the two pillar main body portions and above the pillarbase portion in front view in the headrest upright condition, and asecond coupling portion (35) positioned below the pillar base portion.

According to this aspect, since the support member is coupled to theframe at the first coupling portion and the second coupling portioninterposing the pillar base portion with respect to the verticaldirection, the headrest support device can be supported on the frame ina stable manner.

Preferably, the frame includes a pair of side frames (3) located oneither side, a first upper frame (4) connected between upper ends of theside frames, and a second upper frame (5) connected between parts of theside frames located below the first upper frame; and the support memberis connected to the first upper frame at the first coupling portion, andto the second upper frame at the second coupling portion.

According to this aspect, since the vertical distance between the firstcoupling portion and the second coupling portion can be maximized, theheadrest support device can be supported on the flame in a highly stablemanner.

Preferably, the first upper frame includes a frame main body (4A) and apair of first brackets (7) extending vertically from the frame main bodyin a mutually laterally spaced apart relationship, and the supportmember is secured to the first brackets at a pair of third couplingportions (36) located in a mutually laterally spaced apart relationshipand under the pillar base portion in an upright condition of theseatback.

According to this aspect, since the third coupling portions are furtherprovided at positions closer to the pillar base portion than the secondcoupling portion, the headrest support device can be supported on theframe in a particularly stable manner.

Preferably, the headrest support device further comprises a pillar sidelocking member (50) fixedly attached to the pillar base portion, and asupport member side locking member (60) moveably attached to the supportmember to selectively engage the pillar side locking member to fix arelative angle between the headrest pillar structure and the supportmember, wherein the first coupling portion includes a pair of firstcoupling portions positioned in a mutually laterally spaced apartrelationship, and the pillar side locking member is positioned laterallybetween the two first coupling portions.

According to this aspect, since the first coupling portions are disposedon either side of the pillar side locking member, or, in other words, oneither side of a part where the load is transmitted from the headrestpillar structure to the support member, the headrest support device canbe supported on the frame in a highly stable manner.

Preferably, the first upper frame is provided with a second bracket (11)connected to the first brackets and extending upward relative to theframe main body, and the first coupling portions are connected to thesecond bracket, an abutting portion (95) being formed on an outersurface of the support member opposing the pillar base portion for asurface contact with an outer surface of the first upper frame.

According to this aspect, since the support member is coupled to thefirst upper frame via the first bracket or the second bracket at thefirst coupling portion and the third coupling portions, and the supportmember abuts the first upper frame at the abutting portion thatcorresponds to the pillar base portion, the headrest support device canbe supported on the frame in a stable manner.

Preferably, the second coupling portion is positioned on a vertical linepassing through the pillar side locking member in front view.

According to this aspect, the second coupling portion can support a loadapplied by the pillar side locking member onto the support member in anefficient manner.

Preferably, the support member side locking member is rotatablysupported by the support member via a shaft member, and the supportmember is provided on an outer surface thereof with reinforcing ribsextending vertically and laterally around the shaft member.

According to this aspect, since the part of the support membersurrounding the shaft member to which the load from the headrest pillarstructure is applied via the pillar side locking member and the supportmember side locking member is reinforced by the reinforcing ribs,deformation of the support member is minimized. In particular, since thereinforcing ribs include those extending vertically, the load from theheadrest pillar structure is efficiently transmitted to the first andsecond upper frames.

Preferably, the support member includes a first member and a secondmember that are joined to each other, and the first member, the secondmember and the frame are jointly fastened to one another at at least oneof the first coupling portion (83), the second coupling portion (85) andthe third coupling portions (87).

According to this aspect, the number of bolts required for fastening thefirst member and the second member to each other and fastening thesupport member to the frame can be minimized.

Effect of the Invention

According to the foregoing structure, a headrest support device which issimple in structure and compact in size can be provided.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a front perspective view of a primary part of a vehicle seatprovided with a headrest support device according to an embodiment ofthe present invention;

FIG. 2 is a front perspective view of the headrest support device;

FIG. 3 is a front perspective view of the headrest support device with asecond member removed;

FIG. 4 is a rear perspective view of a primary part of the vehicle seatprovided with the headrest support device;

FIG. 5 is a sectional view taken along line V-V of FIG. 2; and

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

An embodiment of a headrest support device of the present invention isdescribed in the following with reference to the appended drawings. Theheadrest support device of the present embodiment is configured to beused for attaching a headrest to a seatback of a vehicle seat.

As shown in FIG. 1, a seatback 1 is formed by covering a seatback frame2 consisting of a skeletal frame structure with a pad material and askin member. The seatback frame 2 includes a pair of left and right sideframes 3 extending vertically, a first upper frame 4 connected betweenthe upper ends of the respective side frames 3, a second upper frame 4connected between the two side frames 3 under the first upper frame 4.The upper portions of the left and right side frames 3 and a frame mainbody portion 4A of the first upper frame 4 are formed of a singlecontinuous bent pipe member. A front side of a laterally central part ofthe frame main body portion 4A of the first upper frame 4 is deformed soas to define a flat surface facing forward.

As shown in FIGS. 1 to 4, a pair of right and left first brackets 7 arewelded to the flat surfaces of the frame main body portion 4A,respectively, in a symmetric arrangement with respect to a verticalcenter line passing through the center of the frame main body portion4A. Each first bracket 7 is provided with a front side portion 7A facingthe front, and a left and a right side portion 7B extending rearwardfrom the respective lateral edges of the front side portion 7A so thatthe first bracket 7 has a channel cross section having an open sidefacing rearward. Each first bracket 7 is attached to the first upperframe 4 at the rear edges of the left and right side portions 7B. Eachfirst bracket 7 extends upward and downward with respect to the firstupper frame 4. An upper portion 7C of the front side portion 7A of eachfirst bracket 7 protrudes forward with respect to a lower portion 7Dthereof.

As shown in FIGS. 4 to 6, a second bracket 11 extends between the twofirst brackets 7. The second bracket 11 has a plate shape having a majorplane facing the fore and aft direction, and the left and right ends arewelded to the corresponding side portions 7B of the respective firstbrackets 7. The second bracket 11 is spaced from the frame main bodyportion 4A in the forward direction, and projects upward beyond theupper edge of the frame main body portion A.

As shown in FIGS. 1 to 3, the second upper frame 5 consists of a platemember having a major plane facing in the fore and aft direction. Inorder to increase the stiffness of the second upper frame 5, a pluralityof beads are formed at appropriate parts thereof. A fastening seat 5Aprotruding forward is formed at a laterally central position of thesecond upper frame 5 adjacent to the upper edge thereof.

A headrest support device 20 includes a headrest pillar structure 21 anda support member 22 that rotatably supports the headrest pillarstructure 21. In the present embodiment, the support member 22 isattached to the seatback frame 2, and the headrest pillar structure 21is connected to a headrest 24.

The headrest pillar structure 21 includes a pillar base portion 25extending in the lateral direction and a pair of right and left pillarmain body portions 26 extending substantially in parallel with eachother from the left and right end portions of the pillar base portion25, respectively, and substantially in parallel to each other so that ashape of a letter U is substantially defined. The pillar base portion 25and the left and right pillar main body portions 26 are formed bybending a single continuous metal rod or pipe member.

The support member 22 includes a first member 31 and a second member 32that are combined to each other. Although various materials can beselected for the first member 31 and the second member 32, in thepresent embodiment, these two members are formed with plastic material.The first member 31 constitutes the rear side portion of the supportmember 22, and the second member 32 constitutes the front side portionof the support member 22. The first member 31 and the second member 32abut each other at their respective edges. The first member 31 and thesecond member 32 are joined to each other at a pair of left and rightfirst coupling portions 34, a second coupling portion 35, a pair ofright and left third coupling portions 36, and a fourth coupling portion37 as will be described hereinafter.

As shown in FIGS. 5 and 6, the central portion of the second member 32forms a bulging portion 32A that bulges forward relative to the edgeportion. Thus, owing to this bulging portion 32A, an internal space 38is defined between the first member 31 and the second member 32. Asshown in FIG. 2, the edge of the first member 31 protrudes outwardbeyond the edge of the second member 32. An edge rib 41 projectingforward extends along the edge of the first member 31. The end face ofthe edge portion of the second member 32 is disposed so as to abut onthe inner side face of the edge rib 41.

As shown in FIGS. 2 to 4, the first member 31 and the second member 32have the largest lateral width at the central portion with respect tothe vertical direction, and the lateral width progressively decreasesdownward. Specifically, the lower portions of the first member 31 andthe second member 32 are formed in a triangular shape that has onecorner positioned under the other two corners in front view. The upperportions of the first member 31 and the second member 32 are formed in alaterally elongated, substantially rectangular shape in front view. Theupper portions of the first member 31 and the second member 32 arenarrower than the central portions thereof. The upper portion of thefirst member 31 is narrower than the distance between the inner surfacesof the left and right first brackets 7. The lateral widths of theintermediate portions of the first member 31 and the second member 32are greater than the distance between the opposing inner surfaces of theleft and right first brackets 7, and smaller than the distance betweenthe outer surfaces of the left and right first brackets 7 facing awayfrom each other.

As shown in FIGS. 3 and 5, a pair of bearing portions 45 are formed in apart of the internal space 38 defined between the first member 31 andthe second member 32 intermediate between the upper end and thevertically central part of the internal space 38. Each bearing portion45 is formed by a first hearing wall 46 projecting forward from thefront surface 31A of the first member 31 and a second bearing wall 47formed on the rear surface of the second member 32. The first bearingwalls 46 and the second bearing walls 47 are formed on either side of acenter line C passing vertically through the support member 22 in asymmetric manner. Each first bearing wall 46 abuts the correspondingsecond bearing wall 47 so as to jointly form a bearing hole 48. The leftand right bearing holes 48 are aligned to a laterally extending axialline in a coaxial relationship. The pillar base portion 25 is receivedby the left and right bearing holes 48 and is supported so as to berotatable around the laterally extending axial line.

A pair of resilient claws 46B having a suitable flexibility are formedon either side of a groove 46A which forms the rear half portion of thebearing hole 48 of each first bearing wall 46. The resilient claws 46Bare configured to resiliently engage the pillar base portion 25 whenreceived in the groove 46A. Thus, even when the second members 32 arenot assembled to the first members 31, the pillar base portion 25 can beheld received in the grooves 46A. The resilient claws 46B are configuredto be deformed when the pillar base portion 25 is inserted into thegrooves 46A in such a manner as to enable insertion of the pillar baseportion 25 into the grooves 46A. Once the pillar base portion 25 isfully received in the grooves 46A, the resilient claws 46B are restoredto their original shapes, and engage the outer circumference of thepillar base portion 25. Thus, the resilient claws 46B form parts of thebearing holes 48 that rotatably support the pillar base portion 25.Receiving recesses 47A configured to receive the resilient claws 46B areformed on the surfaces of the second bearing walls 47 that about therespective first bearing walls 46.

As shown in FIG. 2, the bulging portion 32A of the second member 32 isprovided with cutout portions 49 on either side portion thereof to passthe corresponding ends of the pillar base portion 25 therethrough. Eachcutout portion 49 is elongated in the fore and aft direction, and thefront end thereof is closed while the rear end thereof extends to andthrough the rear edge of the second member 32. The front end of thecutout portion 49 is formed in a semicircular shape when viewed in sideview so as to conform to the opposing outer peripheral surface of thepillar base portion 25. The cutout portion 49 cooperates with the frontsurface 31A of the first member 31 to form a closed slot.

As shown in FIG. 3 and FIG. 6, a pillar side locking member 50 isprovided in a part of the pillar base portion 25 located between theright and left first bearing walls 46. The pillar side locking member 50is formed by a plate member having a major plane facing laterally, andis fixedly secured to the pillar base portion 25 by welding or the like.The pillar side locking member 50 is positioned on the center line C ofthe pillar base portion 25. A first locking notch 50A and a secondlocking notch 50B are formed on the outer peripheral portions of thepillar side locking member 50. The first locking notch 50A and thesecond locking notch 50B are respectively passed through the pillar sidelocking member 50 in the lateral direction, and open outward in theradial direction around the pillar base portion 25.

A pin 52 projects laterally from the pillar side locking member 50 oneither side in parallel with the pillar base portion 25. A cushioningmaterial 53 is fitted onto one end of the pin 52. The cushioningmaterial 53 may be formed of a flexible material such as rubber andformed in a tubular shape so as to cover the end of the pin 52. A firststopper 54 protrudes forward from the front surface 31A of the firstmember 31, and opposes the one end of the pin 52. The one end of the pin52 abuts against the first stopper 54 via the cushioning material 53 sothat the limit of the rearward pivoting movement of the headrest pillarstructure 21 (clockwise rotation around the pillar base portion 25 asseen from the left side) thereof is defined. The cushioning material 53absorbs the impact when the pin 52 hits the first stopper 54 so that thegeneration of undesired noises can be avoided, and the handlingimpression can be improved. When the one end of the pin 52 abuts againstthe first stopper 54 via the cushioning material 53, the headrest pillarstructure 21 is in the upright position (use position), and the pillarmain body portion 26 extends upward from the pillar base portion 25.

The forward limit position of the pivoting movement of the headrestpillar structure 21 (counterclockwise rotation around the pillar baseportion 25 as viewed from the left) is defined such that the abutting ofthe pillar side locking member 50 onto a second stopper (not shown inthe drawings) formed on the front surface 31A of the first member 31.When the pillar side locking member 50 abuts against the second stopper,the headrest pillar structure 21 is in the retracted position (unusedposition), and the pillar main body portions 26 extend forward from thepillar base portion 25. The headrest pillar structure 21 is thusrotatable between the upright position and the retracted position.

A first biasing member 56 is provided between the headrest pillarstructure 21 and the first member 31 for biasing the headrest pillarstructure 21 toward the retracted position with respect to the firstmember 31. In the present embodiment, the first biasing member 56consists of a torsion coil spring, and includes a coil portion supportedby the pillar base portion 25, one end engaged by the other end of thepin 52, and another end engaged by the front surface 31A of the firstmember 31.

A support member side locking member 60 is rotatably provided on acentral part of the front surface 31A of the first member 31 locatedbelow the bearing portions 45. The support member side locking member 60is formed by a plate member having a major plane facing in the fore andaft direction, and is rotatably supported on the outer circumferentialsurface of a bolt 81 passed through the first member 31 and the secondmember 32 in the thickness wise direction (fore and aft direction). Aswill be described hereinafter, the bolt 81 is passed through a boltinsertion holes (not shown in the drawings) formed in the first member31 and the second member 32 at a fourth coupling portion 37 from therear to the front, and a nut 82 is fastened on the bolt 81 so as tosecurely join the first member 31 and the second member 32 to eachother. The bolt 81 is positioned on the center line C of the supportmember 22.

A locking piece 60A extends outward from an outer peripheral part of thesupport member side locking member 60 in a radial direction with respectto the bolt 81. The support member side locking member 60 is rotatablearound the bolt 81 between an engaged position where the locking piece60A is positioned in the first locking notch 50A or the second lockingnotch 50B and a disengaged position where the locking piece 60A isdisplaced from the first locking notch 50A and the second locking notch50B. The first member 31 is provided with abutting portions (not shownin the drawings) that abut the support member side locking member 60when the support member side locking member 60 is in the engagedposition and the disengaged position. By the abutting of the supportmember side locking member 60 against either abutting portion, therotational range of the support member side locking member 60 withrespect to the first member 31 is determined.

A second biasing member 64 is provided between the support member sidelocking member 60 and the first member 31 for biasing the support memberside locking member 60 toward the engaged position with respect to thefirst member 31. In the present embodiment, the second biasing member 64consists of a tension coil spring that has one end engaged to thesupport member side locking member 60 and the other end engaged to thefront surface 31A of the first member 31.

A first operation member 65 and a second operation member 66 are coupledto the support member side locking member 60. The first operation member65 consists of a belt member made of a woven fabric or the like. Thesecond operation member 66 consists a control cable having a guidesleeve 66A and a cable 66B slidably received in the guide sleeve 66A.One end of the first operation member 65 and one end of the cable 66B ofthe second operation member 66 are rotatably coupled to an outerperipheral part of the support member side locking member 60. Forexample, a support shaft protrudes from an outer peripheral part of thesupport member side locking member 60, and the one end of the firstoperation member 65 and the one end of the cable 66B of the secondoperation member 66 are rotatably supported by the support shaft. Astopper member such as a push nut may be attached to the free end of thesupport shaft.

As shown in FIG. 2, the second member 32 is provided with an opening(not shown in the drawings) through which the first operation member 65passes and an elongated opening 32C through which the cable 66B of thesecond member 32 passes. One end of the opening 32C is disposed in apart opposing the junction at which the first operation member 65 andthe cable 66B are connected to the support member side locking member60, and is provided with a greater width than the remaining part of theopening 32C. Thus, when connecting the first operation member 65 and thecable 66B to the support member side locking member 60, the tool or thelike is accessible to the support member side locking member 60 via theopening 32C. An engagement slot 32E for engaging a locking member 66Cprovided at the end portion of the guide sleeve 66A is formed on thefront side of the second member 32.

As shown in FIG. 1, the other end of the first operation member 65 ispassed through an annular guide member 67 attached to the side frame 3,and then through the pad material and the skin member of the seatback 1before extending out of the seatback 1. By pulling the outer end of thefirst operation member 65 against the biasing force of the secondbiasing member 64, the vehicle occupant can displace the support memberside locking member 60 from the engaged position to the disengagedposition. The other end of the cable 66B of the second operation member66 is connected to the output end of a link mechanism 69. The linkmechanism 69 is connected to a reclining mechanism that rotatablysupports the seatback 1 with respect to the seat cushion, for example,and is configured to operate the second operation member 66 according tothe operation state of the reclining mechanism. For example, it may beconfigured such that when the reclining mechanism is unlocked, the linkmechanism 69 pulls the second operation member 66 against the biasingforce of the second biasing member 64 to displace the support memberside locking member 60 from the engaged position to the disengagedposition. The link mechanism 69 may be supported by the second upperframe 5.

As shown in FIGS. 2 and 3, the first member 31 and the second member 32are joined to each other at a pair of first coupling portions 34 locatedon either lateral side of the upper end part of the first member 31 andthe second member 32, a second coupling portion 35 located at the lowerend part of the first member 31 and the second member 32, a pair ofthird coupling portions 36 located on either lateral side of the centralpart of the first member 31 and the second member 32, and a fourthcoupling portion 37 positioned at the center of the first member 31 andthe second member 32.

In the fourth coupling portion 37, the bolt 81 is passed through boltinsertion holes (not shown in the drawings) formed in the first member31, the second member 32, and the support member side locking member 60,and the nut 82 is fastened to the bolt 8 to join the first member 31 andthe second member 32 to each other. The first member 31 and the secondmember 32 are joined to each other by being joined at the fourthcoupling portion 37. Before the support member 22 is attached to theseatback frame 2, the first member 31 and the second member 32 arejoined to each other at the fourth coupling portion 37. The fourthcoupling portion 37 is positioned at the center of the first member 31and the second member 32 and on the center line C.

The first coupling portions 34 are located above the bearing portions 45of the first member 31 and the second member 32, and symmetrical to eachother with respect to the center line C. In addition, the first couplingportions 34 are located directly above the first bearing wall 46.

The first coupling portions 34 are arranged opposite to the secondbracket 11. In each first coupling portion 34, a bolt 83 is passed intobolt insertion holes (not shown in the drawings) passed through thefirst member 31, the second member 32 and the second bracket 11 in thethickness-wise direction (the fore and aft direction), and a nut 84 isthreaded onto the bolt 83 so that the first member 31, the second member32 and the second bracket 11 are joined to each other by fastening thenut 84. In other words, the first member 31, the second member 32 andthe second bracket 11 are fastened together by the bolts 83 and the nuts84. The first coupling portions 34 are arranged above the first upperframe 4.

The second coupling portion 35 is located on the center line C below thefourth coupling portion 37 (the support member side locking member 60)of the first member 31 and the second member 32.

The second coupling portion 35 is located opposite to the fastening seat5A of the second upper frame 5. In the second coupling portion 35, abolt 87 is passed into bolt insertion holes (not shown in the drawings)passed through the first member 31, the second member 32 and thefastening seat 5A in the thickness-wise direction (in the fore and aftdirection), and a nut 88 is threaded onto the bolt 87 so that the firstmember 31, the second member 32 and the fastening seat 5A are joined toone another. In other words, the first member 31, the second member 32and the fastening seat 5A are fastened together by the bolt 87 and thenut 88.

The third coupling portions 36 are located below the bearing portions 45of the first member 31 and the second member 32 and above the fourthcoupling portion 37 symmetrical to each other about the center line C.Further, the third coupling portions 36 are disposed further outsidethan the respective first bearing walls 46.

The third coupling portions 36 are located opposite to the lower portion7D of the first bracket 7. In each third coupling portion 36, a bolt 87is passed into a bolt insertion hole (not shown in the drawings) passedthrough the first member 31, the second member 32, and the first bracket7 in the thickness-wise direction (the fore and aft direction), and anut 88 is threaded onto the bolt 87 so that the first member 31, thesecond member 32 and the first bracket 7 are fixedly attached to oneanother by fastening the nut 88. In other words, the first member 31,the second member 32 and the first bracket 7 are fastened together bythe bolts 87 and the nuts 88. The third coupling portions 36 arearranged below the first upper frame 4.

As shown in FIGS. 4 to 6, the rear surface 31B of the first member 31 isformed with ribs projecting rearward which include a first to a thirdhorizontal rib 91 to 93 extending in the lateral direction, a pair ofvertical ribs 94 extending vertically, and a plurality of abutting ribs95. The first horizontal rib 91 is positioned between the lower edge ofthe frame main body portion 4A of the first upper frame 4 and the fourthcoupling portion 37. The second and third horizontal ribs 92, 93 arepositioned between the fourth coupling portion 37 and the secondcoupling portion 35 in a mutually vertically spaced apart relationship.The vertical ribs 94 are positioned on either side of the fourthcoupling portion 37 while the lower ends of the vertical ribs 94 extendto the upper edge of the second upper frame 5. The second and thirdhorizontal ribs 92 and 93 and the two vertical ribs 94 intersect eachother. The first and second horizontal ribs 91 and 92 and the verticalribs 94 are disposed so as to surround the fourth coupling portion 37.

The lateral ends of the first horizontal rib 91 extend to the respectivefirst brackets 7. The abutting ribs 95 extend upward from the upper sidesurface of the first horizontal rib 91 on the rear surface 31B of thefirst member 31. The projecting ends of the abutting ribs 95 are formedso as to conform to the outer shape of the first upper frame 4 in acomplementary manner, and are in contact with the outer surface of thefirst upper frame 4. Preferably, the projecting length of each abuttingrib 95 gradually decreases toward the upper end thereof.

As shown in FIG. 1, the free ends of the pillar main body portions 26are inserted into the headrest 24 and retained to the headrest 24. Theheadrest 24 may have, for example, a support structure, a pad materialand a skin member covering the support structure, and a pair of tubularpillar retaining structures provided in the support structure forreceiving the respective pillar main body portions 26. One of the pillarretaining structures may be provided with a locking member configured toselectively engage the pillar main body portion 26 so that the insertionlength of the pillar main body portions 26 in the respective pillarholding portions may be adjusted.

The effect of the headrest support device 20 configured as describedabove is discussed in the following. In this headrest support device 20,since the first coupling portion 34 is positioned in the spacesurrounded by the headrest pillar structure 21 in front view when theheadrest is in use position, the support member 22 and the headrestpillar structure 21 are arranged in a compact manner, and the headrestsupport device 20 can be made compact in size.

Since the support member 22 is joined to the seatback frame 2 at thefirst to third coupling portions 34 to 36 ranging both vertically andhorizontally, the headrest support device 20 can be supported on theseatback frame 2 in a highly stable manner. In particular, since thesupport member 22 is coupled to the first upper frame 4 at the first andthird coupling portions 34 and 36 and to the second upper frame 5 at thesecond coupling portion 35, the coupling portions can range verticallyby a significant distance so that the headrest support device 20 can besupported on the seatback frame 2 in a particularly stable manner.

Furthermore, since the first and third coupling portions 34 and 36 aresecured to the first bracket 7 and the second bracket 11 that extendupward and downward with respect to the first upper frame 4, the firstcoupling portions 34 and the third coupling portions 36 located oneither side of the pillar base portion 25 are both secured to the firstupper frame 4 so that the headrest support device 20 can be supported onthe seatback frame 2 in a stable manner. Furthermore, since the firstcoupling portions 34 are disposed on either side of the pillar sidelocking member 50, or, in other words, the part where the load istransmitted from the headrest pillar structure 21 to the support member22, the headrest support device 20 can be supported in a particularlystable manner.

Further, since the support member 22 abuts onto the first upper frame 4at the plurality of abutting ribs 95, the headrest support device 20 canbe supported on the seatback frame 2 in a stable manner.

Further, in the above described embodiment, it is preferable that thesecond coupling portion 35 is disposed on the vertical line passingthrough the pillar side locking member 50 in front view.

Since the second coupling portion 35 is arranged on the vertical linepassing through the pillar side locking member 50 in front view, thesupport member 22 is enabled to support the load from the pillar sidelocking member 50 in an efficient manner.

The part of the support member 22 surrounding the bolt 81 to which theload from the headrest pillar structure 21 is applied via the pillarside locking member 50 and the support member side locking member 60 isreinforced by the first and second horizontal ribs 91 and 92 and thevertical ribs 94, deformation of the support member 22 is minimized. Inparticular, the load from the headrest pillar structure 21 isefficiently transmitted to the side of the first and second upper frames4 and 5 via the vertical ribs 94.

Since the first member 31 and the second member 32 are fastened togetherby the bolts 83, 85 and 87 for connecting the support member 22 to theseatback frame 2 at the first to third coupling portions 34 to 36, thenecessary number of the bolts can be minimized.

Since the pillar side locking member 50 and the support member sidelocking member 60 are disposed in the internal space 38 substantiallyenclosed by the first member 31 and the second member 32, the padmaterial can be positioned directly around the support member 22 so thatno extra cover material is required to be placed on the support member22. Thereby, the headrest support device 20 can be made simple instructure and compact in size.

The pillar base portion 25 is supported by the bearing holes 48 formedbetween the first member 31 and the second member 32 so as not to bedetached from the support member 22. Therefore, the headrest pillarstructure 21 can be supported on the support member 22 in a stablemanner.

Further, by providing the resilient claws 46B on the first bearing walls46, even when the first member 31 and the second member 32 are separatedfrom each other, the first bearing walls 46 are enabled to keep thepillar base portion 25 held in position. As a result, the assemblingwork for the headrest support device 20 is facilitated. In addition, asthe resilient claws 46B are received in the respective receiving grooves47A, the bearing holes 48 can be defined jointly by the first and secondbearing walls 46 and 47 by abutting the first and second bearing walls46 and 47 to each other.

Since one end (pillar side abutting portion) of the pin 52 abuts ontothe first stopper 54 (abutting portion on the side of the supportmember) so as to define the rotational range of the headrest pillarstructure 21 relative to the support member 22 via the cushioningmaterial 53, striking noises can be avoided, and use comfort can beimproved.

Although the present invention has been described in terms of apreferred embodiment thereof, it is obvious to a person skilled in theart that various alterations and modifications are possible withoutdeparting from the spirit of the present invention.

Glossary of Terms

1: seatback

2: seatback frame

3: side frame

4: first upper frame

4A: frame main body portion

5: second upper frame

7: first bracket

11: second bracket

20: headrest support device

21: headrest pillar structure

22: support member

24: headrest

25: pillar base portion

26: pillar main body portion

31: first member

32: second member

34: first coupling portion

35: second coupling portion

36: third coupling portion

37: fourth coupling portion

38 inner space

45: bearing portion

46: first bearing wall

46B: resilient claw

47: second bearing wall

47A: receiving groove

48: bearing hole

50: pillar side locking member

52: shaft (pillar side abutting portion)

53: cushioning material

54: first abutting portion (support member side abutting portion)

60: support member side locking member

64: second biasing member

65: first operation member

66: second operation member

81, 83, 85, 87: bolt

91: first horizontal rib

92: second horizontal rib

93: third horizontal rib

94: vertical rib

95: abutting rib

The invention claimed is:
 1. A headrest support device comprising: asupport member coupled to a frame of a seatback; and a headrest pillarstructure including a pillar base portion extending laterally andsupported by the support member so as to be rotatable around an axialline of the pillar base portion, and a pair of pillar main body portionsextending substantially vertically from the pillar base portionsubstantially in parallel to each other in a mutually spaced apartrelationship and connected to a headrest; wherein the support member iscoupled to the frame at at least one coupling portion disposed betweenthe two pillar main body portions in front view in a headrest uprightcondition where the headrest is positioned above the seatback; whereinthe coupling portion includes a first coupling portion disposed betweenthe two pillar main body portions and above the pillar base portion infront view in the headrest upright condition, and a second couplingportion positioned below the pillar base portion; wherein the frameincludes a pair of side frames located on either side, a first upperframe connected between upper ends of the side frames, and a secondupper frame connected between parts of the side frames located below thefirst upper frame; and wherein the support member is connected to thesecond upper frame at the second coupling portion.
 2. The headrestsupport device according to claim 1, wherein the support member isconnected to the first upper frame at the first coupling portion.
 3. Theheadrest support device according to claim 2, wherein the first upperframe includes a frame main body and a pair of first brackets extendingvertically from the frame main body in a mutually laterally spaced apartrelationship, and the support member is secured to the first brackets ata pair of third coupling portions located in a mutually laterally spacedapart relationship and under the pillar base portion in an uprightcondition of the seatback.
 4. The headrest support device according toclaim 3, further comprising a pillar side locking member fixedlyattached to the pillar base portion, and a support member side lockingmember moveably attached to the support member to selectively engage thepillar side locking member to fix a relative angle between the headrestpillar structure and the support member, wherein the first couplingportion includes a pair of first coupling portions positioned in amutually laterally spaced apart relationship, and the pillar sidelocking member is positioned laterally between the two first couplingportions.
 5. The headrest support device according to claim 4, whereinthe first upper frame is provided with a second bracket connected to thefirst brackets and extending upward relative to the frame main body, andthe first coupling portions are connected to the second bracket, anabutting portion being formed on an outer surface of the support memberopposing the pillar base portion for a surface contact with an outersurface of the first upper frame.
 6. The headrest support deviceaccording to claim 4, wherein the second coupling portion is positionedon a vertical line passing through the pillar side locking member infront view.
 7. The headrest support device according to claim 4, whereinthe support member side locking member is rotatably supported by thesupport member via a shaft member, and the support member is provided onan outer surface thereof with reinforcing ribs extending vertically andlaterally around the shaft member.
 8. The headrest support deviceaccording to claim 3, wherein the support member includes a first memberand a second member that are joined to each other, and the first member,the second member and the frame are jointly fastened to one another atat least one of the first coupling portion, the second coupling portionand the third coupling portions.
 9. The headrest support deviceaccording to claim 5, wherein the second bracket extends between the twofirst brackets.
 10. A headrest support device comprising: a supportmember coupled to a frame of a seatback; a headrest pillar structureincluding a pillar base portion extending laterally and supported by thesupport member so as to be rotatable around an axial line of the pillarbase portion, and a pair of pillar main body portions extendingsubstantially vertically from the pillar base portion substantially inparallel to each other in a mutually spaced apart relationship andconnected to a headrest; and a pillar side locking member fixedlyattached to the pillar base portion; and a support member side lockingmember moveably attached to the support member to selectively engage thepillar side locking member to fix a relative angle between the headrestpillar structure and the support member, wherein the support member iscoupled to the frame at least one coupling portion disposed between thetwo pillar main body portions in front view in a headrest uprightcondition where the headrest is positioned above the seatback, and thesupport member side locking member is rotatably supported by the supportmember via a shaft member, and the support member is provided on anouter surface thereof with reinforcing ribs extending vertically andlaterally around the shaft member.
 11. The headrest support deviceaccording to claim 10, wherein the coupling portion includes a firstcoupling portion disposed between the two pillar main body portions andabove the pillar base portion in front view in the headrest uprightcondition, and a second coupling portion positioned below the pillarbase portion, and the reinforcing ribs are positioned between the firstcoupling portion and the second coupling portion.
 12. The headrestsupport device according to claim 10, wherein the frame includes a pairof side frames located on either side, and a first upper frame connectedbetween upper ends of the side frames; the support member is connectedto the first upper frame at the first coupling portion, and to thesecond upper frame at the second coupling portion; the coupling portionincludes a fourth coupling portion disposed between the first couplingportion and the second coupling portion, the support member is providedon the outer surface thereof with abutting ribs being in contact withthe outer surface of the first upper frame; and the reinforcing ribsinclude a first horizontal rib extending in the lateral directionbetween the abutting ribs and the forth coupling portion.
 13. Theheadrest support device according to claim 10, the seatback forms a partof a vehicle seat.
 14. A vehicle seat, comprising: a seatback having aframe, a pad material and a skin member; and a headrest support deviceconfigured to attach a headrest to the seatback, wherein the headrestsupport device comprises: a support member coupled to the frame; and aheadrest pillar structure including a pillar base portion extendinglaterally and supported by the support member so as to be rotatablearound an axial line of the pillar base portion, and a pair of pillarmain body portions extending substantially vertically from the pillarbase portion substantially in parallel to each other in a mutuallyspaced apart relationship and connected to the headrest, wherein thesupport member is coupled to the frame at at least one coupling portiondisposed between the two pillar main body portions in front view in aheadrest upright condition where the headrest is positioned above theseatback, the coupling portion includes a first coupling portiondisposed between the two pillar main body portions and above the pillarbase portion in front view in the headrest upright condition, and asecond coupling portion positioned below the pillar base portion, theframe includes a pair of side frames located on either side, a firstupper frame connected between upper ends of the side frames, and asecond upper frame connected between parts of the side frames locatedbelow the first upper frame; and the support member is connected to thesecond upper frame at the second coupling portion.
 15. The vehicle seataccording to claim 14, wherein the support member is connected to thefirst upper frame at the first coupling portion.
 16. The vehicle seataccording to claim 14, wherein the first upper frame includes a framemain body and a pair of first brackets extending vertically from theframe main body in a mutually laterally spaced apart relationship, andthe support member is secured to the first brackets at a pair of thirdcoupling portions located in a mutually laterally spaced apartrelationship and under the pillar base portion in an upright conditionof the seatback.
 17. The vehicle seat according to claim 15, furthercomprising a pillar side locking member fixedly attached to the pillarbase portion, and a support member side locking member moveably attachedto the support member to selectively engage the pillar side lockingmember to fix a relative angle between the headrest pillar structure andthe support member, wherein the first coupling portion includes a pairof first coupling portions positioned in a mutually laterally spacedapart relationship, and the pillar side locking member is positionedlaterally between the two first coupling portions.
 18. The vehicle seataccording to claim 15, wherein the first upper frame is provided with asecond bracket connected to the first brackets and extending upwardrelative to the frame main body, and the first coupling portions areconnected to the second bracket, an abutting portion being formed on anouter surface of the support member opposing the pillar base portion fora surface contact with an outer surface of the first upper frame.